Adhesives coatings and laminates utilizing ethylene copolymers and coal-tar pitch

ABSTRACT

THERMOPLASTIC COMPOSITIONS OF MATTER COMPRISING COALTAR PITCH AND A MATERIAL SELECTED FROM (1) A TERPOLYMER OF ETHYLENE, VINYL ACETATE, AND AN ETHYLENICALLY-UNSATURATED CARBOXYLIC ACID AND (2) A MIXTURE OF COPOLYMERS OF ETHYLENE AND VINYL ACETATE AND OF ETHYLENE AND AN ETHYLENICALLY-UNSATURATED CARBOXYLIC ACID, EXHIBITING HIGH STRENGTH IN SHEAR AND PEEL OVER A WIDE TEMPERATURE RANGE, ARE PREPARED AND USED AS ADHESIVES AND COATINGS. LAMINATED MATERIALS UTILIZING SUCH COMPOSITIONS OF MATTER ARE ALSO DISCLOSED.

June 4, 1974 a. F. SNYDER ETAL 3,814,712

ADHESIVES COATINGS AND LAMINATES UTILIZING ETHYLENE COPOLYMERS ANDCOAL-TAR PITCH FiledNov. 24, 1971 O m O /AMPL lF/Ef? CLAMP 0 O O L. .l o

Q P/CKUP O O TRANSDUCER M 8 ns-5r O O SPEC/MEN 400/0 8 OSCILLATOR OEXC/Z'Ef? O O TRANSDUCER 1 COMPL E X MODUL as Q Q Q g ,.--Rc0/?0R UnitedStates Patent Oflice 3,814,712 Patented June 4, 1974 ADHESIVES COATINGSAND LAMINATES UTILIZ- llgfijgTHYLENE COPOLYMERS AND COAL-TAR George F.Snyder, Franklin Township, Westmoreland County, and Robert M. Stewart,Monroeville Borough, Pa., assignors to United States Steel Corporation,Pittsburgh, Pa.

Continuation-impart of abandoned application Ser. No. 692,295, Dec. 21,1967. This application Nov. 24, 1971, Ser. No. 201,861

Int. Cl. C08f 45/52 US. Cl. 260-28.5 AS 16 Claims ABSTRACT OF THEDISCLOSURE Thermoplastic compositions of matter comprising coaltar pitchand a material selected from (1) a terpolymer of ethylene, vinylacetate, and an ethylenically-unsaturated carboxylic acid and (2) amixture of copolymers of ethylene and vinyl acetate and of ethylene andan ethylenicallyunsaturated carboxylic acid, exhibiting high strength inshear and peel over a wide temperature range, are prepared and used asadhesives and coatings. Laminated materials utilizing such compositionsof matter are also disclosed.

This application is a continuation-in-part of our earlier copendingapplication, Ser. No. 692,295, filed Dec. 21, 1967, now abandoned.

BACKGROUND OF THE INVENTION Many types of resins have heretofore beenadded to a coal-tar pitch to take advantage of its low cost anddurability and to overcome its mechanical Weakness, brittleness and pooradhesion. Thus, Downey USP 3,219,064 provides a pipe coating tapecomprising coal-tar pitch, poly-vinyl chloride and a plasticizer andParkinson USP 3,361,692 provides a coating and adhesive compositioncomprising coal-tar pitch and an ethylenevinyl acetate copolymer.Although these as well as other prior art compositions do enhance thesuitability of coal-tar pitch for use as an adhesive and coating, theresulting compositions are either too expensive or do not havesufiiciently good adhesive properties to provide a generally usefulcomposition.

Olefinic polymers are known to be inert and flexible but exhibit pooradherence to most substrates and have poor stress crack resistance.Thus, Baum, USP 3,410,928, to provide an olefinic polymer compositionhaving increased adhesive and stress resistant properties, adds anethylene-acrylic coor terpolymer to his olefinic polymer to provide aprintable, grease resistant composition with improved adhesion. Suchcompositions however have poor abrasion and heat resistance, and aretherefore not suitable for use in applications where such qualities aredesirable.

Coal-tar pitch and asphalt compositions have been used to coatgalvanized steel culverts to improve abrasion and corrosion resistance.Asphalt dipped culvert coating is a thick (50 mils) coating obtained bydipping sections of formed culvert pipe into molten asphalt.Disadvantages associated with this coating are (1) a non-uniform coatingthickness, (2) poor adhesion, (3) poor low temperature performance, (4)the coating makes the pipe sticky and difiicult to handle, (5) firehazard, (6) the size of the dip tank puts a limit on the length ofculvert sections possible, (7) subject to microbial attack, and (8)hydrogen sulfide permeability, and (9) air pollution hazard. Y Asbestosbonded culvert coatings are also used. Sheets of asbestos, impregnatedwith asphalt are bonded to steel directly following the galvanizingoperation using the still molten zinc as the bonding agent.Disadvantages associated with this product are (1) its high cost, (2)dependence upon sheet galvanizing operation, (3) availability only incut lengths not suitable for spiral Wound culverts, (4) subject tomicrobial attack, (5) hydrogen sulfide permeable, (6) poor control ofzinc coating thickness and (7) difficulties in handling and shipping,(8) fire hazard in dip tank, and (9) air pollution hazard.

Ideally, a culvert coating should possess the following characteristics:(1) excellent abrasion and corrosion resistance, (2) excellent adhesionand uniformity of coating thickness, (3) low cost, (4) suitable forcoating coils for use in spiral culvert machines, (5) elimination of thedip coating step, (6) clean and easy to handle and ship, (7) hydrogensulfide resistant, and 8) resistant to microbial attack.

SUMMARY OF THE INVENTION We have now discovered that the addition ofcoal-tar pitch to an ethylene terpolymer or a mixture of two ethylenecopolymers yields an adhesive and coating material that has excellentadhesive and protective properties. The addition of coal-tar pitch tothe terpolymer or copolymer mixture in an attempt to lower the cost ofthe adhesive, surprisingly, through a synergistic effect, increased theadhesive properties of the combination to a level above that of itsindividual components.

We have determined that one of the copolymers must be an ethylene-vinylacetate copolymer. The second copolymer must be an ethylene-carboxylicacid copolymer where the carboxylic acid is ethylenically unsaturatedand contains from 3 to 8 carbon atoms. When the coal-tar pitch comprisesabout 10 to weight percent of the composition, the ethylene-vinylacetate copolymer comprises about 5 to weight percent and theethylene-carboxylic acid copolymer comprises about 5 to 85 weightpercent, our novel composition exhibits surprisingly high tensile shearand peel strengths, even at temperature extremes, improved moistureresistance and resistance to bacterial attack, decreased sensitivity todirty surfaces due to the detergent effect of the composition and allowsthe use of decreased extrusion pressures.

When the pitch is added to an ethylene terpolymer, the other twocomponents of the terpolymer must be vinyl acetate and anethylenically-unsaturated carboxylic acid containing from 3 to 8 carbonatoms. The beneficial effect of our invention is obtained when thecoal-tar pitch comprises about 10 to 75 weight percent of thecomposition and the terpolymer comprises about 25 to Weight percent ofthe composition.

The compositions of our invention have been found to be highly useful asadhesives for both porous and nonporous materials. It is useful as acoating, especially for exterior surfaces, i.e. industrial roofing andsiding, because of its insensitivity to weathering and to low or hightemperatures. Surprisingly, a thin layer of our composition laminatedbetween steel sheets was found to have" DETAILED DESCRIPTION A pitchsuitable for the purposes of the invention is preferably that derivedfrom coal tar. Useful pitches range in ring-and-ball softening pointsbetween about 70 C. and 200 C., a preferred range being between about C.and C.

The ethylene copolymers with unsaturated carboxylic acids, suitable forpurposes of this invention are known.

A method for preparing copolymers is disclosed in Graham et al. USP3,132,120, issued May 5, 1964. The ethylenically-unsaturatedcarboxylic-acid component of the resin may comprise a monocarboxylic ordicarboxylic acid having from 3 to 8 carbon atoms such as acrylic acid,methacrylic acid, ethacrylic acid, fumaric acid, maleic acid, itaconicacid, crotonic acid and the like. Useful copolymers may vary in meltindex from about 0.1 to about 400, the preferred range being betweenabout and 40. The acid content of useful copolymers may range betweenabout 0.1% and 75% by weight of the copolymer. The acid range ofcommercially available copolymers with acrylic acid is between about0.1% and 40% by weight of the copolymer. The preferred acid range of thelatter is between about 2% and 20%, since above about 20% the productsincrease in crystallinity. In the above classification, usefulcommercially available ethylene-acid copolymers include Zetafin QX3623.7 and QX 3623.24, sold by Dow Chemical Company; 'EAA 9000, 9300 and9320, sold by Union Carbide Corporation; and EMA 22, sold by MonsantoCompany.

The ethylene-vinyl acetate copolymers are known. A method for preparingthem is disclosed in Perrin et a1. USP 2,200,429, issued May 14, 1940.Useful copolymers are those having a vinyl acetate content between about5% and 50% by weight, preferably between about 15% and 40% by weight.Useful copolymers are those having a melt index between about 0.2 and500, preferably between about 0.5 and 175. In the above classification,useful commercially available ethylene-vinyl acetate copolymers includeElvax 40, 150, 210, 220, 240, 250, 260, 310, 350, 360, 420, 460 and EP3710, sold by E. I. du Pont de Nemours & Company; and Co-MER EVA 303,305, 308, 501, 505 and 508, sold by Union Carbide Corporation.

Where the terpolymer rather than the mixture of copolymers is combinedwith the pitch, the vinyl acetate and carboxylic acid components of theterpolymer are subject to the same limitations discussed above inrelation to the ethylene copolymers. Best results are obtained when thecomposition is in the preferred range of about 60 to 75 weight percentethylene, about 2 to 20 weight percent acrylic acid, and about 15 to 40weight percent vinyl acetate.

It has been found that the broad limits for an adhesive compositioncomprise in percent by weight between about 10 and 75 percent of acoal-tar pitch, between about 5 and 85% of a copolymer of ethylene andvinyl acetate, and between about 5 and 85% of an ethylene-acidcopolymer. Preferably, a composition of three components comprises byweight between about 25% and 50% pitch, between about 20% and 40%ethylene-vinyl acetate copolymer and between about 2 0% and 40%ethylene-acid copolymer.

Where the terpolymer is used the broad limits for the compositioncomprise in weight percent between about 10 and 75 percent of a coal-tarpitch and between 25 and 90 percent of an ethylene-vinylacetate-carboxylic acid terpolymer. Preferably, the composition shouldcomprise between about 25 and 50 weight percent pitch and between about50 and 75 weight percent terpolymer.

It has been found that the above compositions, among other improvedproperties, showed unexpectedly large improvements in peel strength overcommercially available compositions. Comparison tests were made of thepeel strengths at 73 F. according to ASTM Method D903-49. For 100%Zetafin QX 3623.7 (ethylene-acid copolymer) and for 100% Elvax 260(ethylene-vinyl acetate copoly mer) the pounds of pull per inch of bondwidth (p.p.i.) were the same, namely, 35. For 40% pitch and 60% Elvax260 by weight the p.p.i. was 30. When as little as 1% by weight ZetafinQX 3623.7 was included in the latter two-component composition, therewas a decrease in extrusion pressure, resulting in easier processing aswell as other advantages and benefits. It was found that when thepercentage of Zetafin QX 3623.7 was increased, the peel strength of thecomposition increased until a peel strength of p.p.i. was obtained witha composition comprising one third each by weight of pitch, Zetafin QX3623.7 and Elvax 260. It is evident that while a pitch- Elvax 260composition has fair adhesive properties, somewhat similar to those ofthe individual copolymers, unexpectedly enhanced or synergisticproperties are found by adding an ethylene-acid copolymer to a2-component composition comprising pitch and an ethylene-vinyl acetatecopolymer. While this is an unexpected and outstanding improvement,other advantages and benefits of the compositions will be discussedhereinafter.

It has also been found that the above compositions may be made lesscostly or given improved properties by the addition thereto of the usualcommercial filler materials, in the usual quantities. These may includealuminum silicate, talc, aluminum powder and precipitator dust, aproduct of a steel plant which is largely iron oxide. Broadly, up toabout 40% by weight of a finely-divided filler material may be added,preferably up to about 20% by weight of the total composition.

In one embodiment of our invention, the pitch-polymer composition islaminated between two metal sheets. We prefer to laminate the materialsby heating the metallic sheet to at least 400 F. and passing it and afilm of the desired thickness of the pitch-polymer composition through anip-roll. The second metal sheet is applied in like manner.Surprisingly, the composition acts not only as an adhesive but also as avisco-elastic material which exhibits vibration dampening properties.The vibration dampening laminates comprise a metallic skin, a middlevisco-elastic layer and a bottom constraining layer.

A vibrating metallic member can be damped by contacting it with anothermaterial in such a way that energy is transferred and transformed intoheat. The effectiveness of a sound damping material may be determined onthe basis or reverberation time which is defined as the time required(in seconds) for a decrease of 60 decibels in the sound level of thespecimen being tested. Materials that provide reverberation time valuesof 0.40 second or less are considered very effective sound and vibrationdampers. The reverberation time is dependent upon (1) the thickness ofthe visco-elastic layer, (2) the thickness of the constraint layer, and(3) the temperature. We have discovered that when our composition isused as the viscoelastic layer between steel sheets, the laminateperforms its vibration damping function when the visco-elastic layer isat least 0.008" thick, the constraining layer is at least 0.009" thickand the temperature is between 50 and 300 F. We have also determinedthat further improvements in the sound damping properties of thelaminate are obtained up to the point where the three layers of thelaminate are of equal thickness. Visco-elastic or constraining layersthicker than the base layer result in no further improvement. Bestresults are obtained when the visco-elastic and constraining layers areat least 0.015 thick and the temperature is between and 200 F. Metalsother than steel may be used as either one or both the base andconstraint layers.

The pitch-polymer composition has been found useful as a water-proofinglayer on concrete or steel bridge decks. In addition to serving as anadhesive to bond a bituminous hot mix wearing surface to the bridgedeck, the composition is also an excellent water resistant membrane andprotects the bridge deck from intrusion by salt or other water-homecorrosive agents. In this embodiment, our composition is applied as afilm having a thickness of from about 20 to about 50 mils.

The pitch-polymer composition has been found to be especially suitablefor use as a protective coating on steel culvert pipe. Coated metalculvert pipe is widely used in conduits for gravity drainage of water inhighway, railway, airport, municipal, industrial and otherinstallations.

The culvert pipe must have acceptable durability and resistance tomaterial degradation from abrasion by hydraulic trafiic and fromcorrosion and other modes of chemical or electrolytic deterioration.

Deterioration of culvert pipe metals is caused by corrosion and/orabrasion. Corrosion is the major and most persistent cause of damage:materials loss associated with corrosion usually originates on theculverts interior surface and progresses toward the exterior surface.Experience has shown that properly applied coatings can significantlyextend metal culvert pipe service life. Bituminous coating is widelyused, affording protection additional to that provided by the basicgalvanized coating. To be most eflective, it must adhere well to theunderlying metal and provide insulation from the corrosive environment.A need is indicated for the deveolpment of metal culvert pipe coatingslacking the undesirable qualities of bituminous type coatings, i.e.,variable thickness and adherence, softness, high susceptibility todamage, stickiness, dirtiness in handling, fire and air pollution, etc.The composition of our invention satisfies this need. Our adhesivecomposition, applied to metal culvert pipe under controlled conditionsas a film having a thickness of from to 30 mils, preferably -20 mils,provides a combination of corrosion and abrasion protection superior tothat given by any previous material.

Yet another embodiment of our invention is the use of our composition inthe form of a tape either alone or laminated to a backing for use incoating metal pipe. Where the composition is used alone, it ispreferable to wrap the tape with a material such as paper to providepre-service protection to the pipe. Excellent results have been obtainedusing a paper-polyethylene-copolymer pitch resin tape. The backing forthe tape may be selected from any of the conventionally used materialssuch as paper, resin impregnated paper, felt, or glass fiber. We preferto use a two-component backing of paper and polyethylene. Previous pipecoating systems have required that the pipe be primed. We have now foundthat our novel tape can be applied to an unprimed heated pipe. We havefound that temperatures in the range of ZOO-500 F. are suitable and mostprefer temperatures in the range of 220-400 F. Best results have beenobtained at 275- 350 F.

The thickness of the copolymer resin composition may be varied widely.We prefer to maintain the thickness in the range of 10 to 50 mils.

The composition may also be used in the form of a tape either alone orlaminated to a backing for use as an impact and abrasion resistant wrapto protect coal-tar enamel coatings applied to steel pipe. In thisapplication, the pipe is coated with coal-tar enamel (CTE) byconventional coating equipment; however, instead of overwrapping withasbestos felt, glass mat or kraft paper, the C'IE is protected by theuse of our composition in the form of a tape either alone or laminatedto a backing. The CTE should be applied in a thickness of about -90mils, preferably about 30-50 mils. The thickness of the pitchpolymercomposition may vary widely but we prefer to maintain a thickness ofabout 10-50 mils. The CI'E, when applied at a temperature of about400-550 F. supplies sulficient heat to bond the tape to the CTE. Thisbond can be strengthened by using a coal-tar-synthetic rubber primerapplied to the tape.

The composition may be used in yet another method to protect steel pipe;direct extrusion coating. In this method the pipe is cleaned, then fedthrough a crosshead die on an extruder and a continuous sleeve of thecomposition is extruded around the pipe. Bonding of the coating to thepipe can be enhanced using a primer or mastic; however, we prefer toenhance the bonding by heating the unprimed pipe to about 125-400" F.before coating and after coatings, water quenching to quickly cool thepipe. Best results have been obtained using a temperature of aboutISO-225 F. The thickness of the coating can vary 6 widely; however, weprefer to maintain it in the range of about 10-40 mils.

The pitch-polymer composition is also highly useful in the manufactureof laminated curtain wall panels for both interior and exterior use. Inthis embodiment of our invention a base layer which may be galvanizedsteel, aluminum coated steel, carbon steel, aluminum, thermosetreinforced plastic, or any other material adaptable for use as a curtainwall is coated with an adhesive layer of our composition. The base layermay vary widely in thickness depeending on the specific use. We havefound that steel base layers of about 22-26 gage give the best results.For exterior use, galvanized steel having a zinc coating weight of about1 A-2 oz./ sq. ft. has been found to give excellent results. Theadhesive and base layers are laminated by heating the base layer to atemperature of about 400- 450 F. and passing the two layers through anip-roll.

Where the difierence in magnitude of coeflicient of thermal expansionbetween the base and face layers is quite large and/or where the panelis to be used in areas of extreme temperature variation, the preferredmethod of applying our adhesive comprises maintaining a molten body ofthe adhesive above the base layer and dripping or spraying the adhesiveonto the base layer. The thickness of the adhesive layer may varywidely. Thickness in the range of about 10 to 50 mils are satisfactoryfor most purposes, with 15 to 30 mil thicknesses being preferred.

The face layer may be applied to the two element system while still hot.Alternatively, the base-adhesive laminate may be reheated to about400-450 F. and the face layer applied. This face layer may be a woodveneer, plywood, a plain or embossed or otherwise decorated metallicsheet, or any of a wide number of other materials.

The face layer need not be a continuous sheet. We contemplate applyingaggregate to the base-adhesive laminate to give various attractiveeffects. Any type of aggregate may be used. River sands and gravels,traprock, marble chips, quartzite, and crushed steel mill slag areespecially attractive.

If the aggregate is composed of particles varying widely in size, it ispreferable to size the material into two on more fractions beforeapplication. For example, the aggregate may be sized into /2 +4 meshsize, -4 +10 mesh size and 10 mesh size fractions.

The aggregate is applied by heating the base-adhesive laminate to about400-450 F., dropping the agreate onto the softened adhesive and runningthe composition through a soft rubber roller to embed the particles inthe adhesive layer. The laminate is then quenched to harden the adhesiveand the excess, non-adhering aggregate is removed.

A complete understanding of the invention may be obtained from thefollowing typical examples of our process showing how the compositionsare made and giving some of the properties thereof. The designatedproperties were determined by standard ASTM methods, more particularly,D1002-5 3T (tensile shear strength) and D903-49 (peel strength).

Examples 1-6 Zetafin QX 3623.7 is a commercially available proprietarycopolymer of ethylene and acrylic acid. It has an acid content of about6.8% by weight and a melt index of about 5. Elvax 260 is a commerciallyavailable proprietary copolymer of ethylene and vinyl acetate. It has avinyl acetate content of about 28% and a melt index of about 6.

In Example 1, equal parts or percent by weight of Zetafin QX 3623.7,Elvax 260 and a coal-tar pitch having a ring-and-ball softening point ofabout C. were mixed for 20 minutes in a twin-shell blender and then fedto an extruder preheated to between 240 and 300 F. Metering screws wereused having a length to diameter ratio of 24 to 1 and a compressionratio between about 3 to l and 4 to 1. The mixture was extruded as a0.010

inch thick film and test samples prepared therefrom. In Examples 2-5,the proportions of a similar pitch were varied. The tensile shear andpeel strengths became appreciably lower only after about 60% pitch wasused. Comparing Examples 1 and 6 using 150 C. and 110 C. pitches,respectively, the test results were a bit lower generally for Example 6.The results are tabulated in Table 1.

TABLE 1 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5

Examples 7-11 Example 1 was repeated as Examples 7-11 to illustrate theeifect on the composition of a change in the ethyleneacid copolymer. Theresults are tabulated in Table 2, the Example 1 results being added forcomparison. More particularly, for Zetafin QX 3623.7 there wassubstituted Zetafin QX 3623.24, EAA 9300, EAA 9000, EAA 9320 and EMA 22in Examples 7-11, respectively. Zetafin QX 3623.24 is anethylene-acrylic acid copolymer having an acid content of about 6.8% anda melt index of about 40. EAA 9300 is an ethylene-acrylic acid copolymerhaving an acid content of about and a melt index of about 50. EAA 9000is an ethylene-acrylic acid copolymer, having an acid content of about14% and a melt index of about 5. EAA 9320 is an ethylene-acrylic acidcopolymer, having an acid content of about 16% and a melt index of about50. EMA 22 is an ethylene-maleic acid copolymer, having an acid contentof about 70%. Tensile shear and peel strengths of the respectiveexamples varied somewhat from each other but not an appreciable extent,with the exception of Example 11. Even for Example 11 the peel strengthat 73 F. of is the same as for a 2-component composition of pitch and anethylene-vinyl acetate copolymer.

TABLE 2 Ex. 1 Ex.7 Ex.8 Ex.9 Ex. 10 Ex. 11

Components, weight Example 1 was repeated as Examples 12-14, toillustrate the effect on the composition of a change in theethylene-vinyl acetate copolymers. The results are tabulated in Table 3,the Example 1 results being included for 8 comparison. Moreparticularly, for Elvax 260, there was substituted Elvax '360, 460 andEP 37 10 in Examples 12- 14, respectively. Elvax 360 has a vinyl acetatecontent of about 25% and a melt index of about 2. Elvax 460 has a vinylacetate content of about 18% and a melt index of about 2.5. Elvax EP3710 has a vinyl acetate content of about 9.5% and a melt index of about0.8. The tensile shear and peel strengths of the respective examplesvaried somewhat from each other.

TABLE 3 EX. 1 Ex. 12 EX. 13 EX. 14

Com onents, weight ereent:

lgtch 150 0---? 331 Zetafin QX 3623 7- 331 331 33}; 33}; Flvax 260 33}:Elvax 300 33k Elvax 460 33}; Elvax EP 3710- 33}; Properties; tensileshear strength,

as. a p 40 F 3,900 2,600

F 1,000 250 Peel strength (180) 40 F 55 45 73 F 70 60 F 55 35 Examples15-21 Using an Example 1 composition, these examples illus trate thatrelatively good peel strength results may be obtained at 73 F.regardless of the substrate surface preparation of cold rolled carbonsteel or galvanized steel. It should be pointed out that with allgalvanized steel substrates, the adhesion was sufiicient to cause thezinc coating to delaminate from the steel base. The results aretabulated in Table 4.

Examples 22-25 Example 1 was repeated as Examples 22-25 to illustratethe effect on the composition (equal weight percents of the Example 1components) by the addition thereto of typical commercial fillers invarious amounts. The results are tabulated in Table 5, the Example 1results being included for comparison. More particularly, in Example 22,Aluminum Silicate, Grade ASP 400 provided 20% by weight of thecomposition, the remainder being equal weight percents (26%%) of C.pitch, Zetafin QX 3623.7 and Elvax 260. Some of the tensile shearstrength results were somewhat better and some of the peel strengthresults somewhat poorer than results for Example 1. In Example 23, thefiller represented a mixture of 20% aluminum silicate and 2% aluminiumpowder. Test results were somewhat the same as for Example 22. InExample 24, steel mill precipitator dust, largely iron oxide, was usedto 11% of the total composition. The test results were about the same asfor Examples 22 and 23, except for a poorer peel strength at '40 -F. InExample 25, talc represented 30% of the composition, the test resultsbeing somewhat similar to those obtained with other fillers.

TABLE Ex. 1 Ex. 22 Ex. 23 Ex. 24 Ex. 25

ASP 40020 aluminum Preeipitator dust-11-.. Talc-30.

Powder-2.

Examples 26-28 the laminated panel was squeezed in a hot press to obtainthe desired thickness of the visco-elastic layer.

The procedure of Example 1 was repeated in Examples 26-28 to illustratethe unexpected results obtained with a Z-component composition of anethylene-vinyl acetate copolymer and ethylene-acid copolymer, ascompared to the results obtained with the individual copolymers. Theresults are tabulated in Table 6, the Example 1 results being added forcomparison. More particularly, 100% Elvax 260 composition was tested inExample 26, 100% Zetafin QX 3623.7 composition in Example 27 and 50% ofeach by weight in a 2-component composition in Example 28. Where a highpeel strength is essential, the Example 28 composition results at thethree temperatures were unexpectedly higher than the corresponding peelstrength results for Examples 26 and 27 The unpredictability of theproperties obtained with a Z-component copolymer composition as comparedwith the results obtained with the individual copolymers is reflected inthe diverse lap shear strength properties. As previously pointed out,the 3-component composition of Example 1 had unexpectedly higher peelstrength properties at the three temperatures than were obtained withthe 2-component composition of Example 28 and the single-componentcompositions of Examples 26 and 27.

TABLE 6 It will be evident from the foregoing that our inventionprovides desirable adhesive compositions. While these compositions areprimarily adhesives, they are also useful as protective coatings,moldings, extrusions and films. Moldings, extrusions and films may beprepared in accordance with usual extrusion practices. The adhesivesresistance to moisture was shown by immersing ASTM D903 peel testspecimens in water at 73 F. for 28 days. At the end of this period noloss of peel strength was detected with carbon steel, stainless steeland galvanized steel substrates. For these adhesives, the resistance ofpitch to microbial degradation was not lessened by copolymer addition.

Example 29 To show the vibration dampening eflect of laminatedcompositions of our invention, test specimens were prepared by cleaningthe metallic base and constraining layers in an alkaline solution. Thebase layer was heated to 420- 430 F. and the visco-elastic film wasbonded to the base layer on a nip-roll. The constraining layer wasplaced on the visco-elastic layer and the entire panel heated to 420-430 F. and passed through the nip-roll to uniformly bond theconstraining layer to the visco-elastic layer. Finally,

In the following tests, the base and constraining layers are 0.024 inchthick cold-rolled sheet steel. Table 7 lists the sound-dampeningproperties for laminates having difierent thickness of a visco-elasticlayer of the following The test equipment is shown in the figure. Thecomplex modulus was located inside a bench oven, which providesacoustical insulation as well as serving as a chamber for testing of thedesired temperatures. To obtain temperatures lower than roomtemperature, carbon dioxide was evaporated in the oven.

In the sound-dampening test, energy is induced into a test specimen thatis clamped at one end andv free at the other. Energy is induced at allfrequencies between 20 and 20,000. Hertz and measurements are made ofthe energy transmitted through the specimen.

The results obtained show that excellent sound-dampening was obtainedwhen the visco-elastic layer was ap proximately /3 the thickness of thebase layer. Further improvements in the sound-dampening properties wereobtained up to the point where the three layers of the laminate were ofequal thickness, but visco-elastic layers thicker than the base layerresulted in no further improvement.

TABLE 7 Room-temperature sound-dampening r0 rties tor laminates withvarious thicknesses of visco-elagti l ayer (Nexus P10t.3)

A Thickness oi visco elastic layer, inch At 1 i I d db RT l Ai=Wldth (inHz.) oi the frequency-resonance peak at the half power points (that is,3 db below the peak).

1 i= Frequency (in Hz.) at the resonance peak.

4 db=Amplitude (in db) of the frequency-resonance peak.

l RT= Reverberation time (the time, in seconds, required for a de creaseof 60 db in the sound level).

ET is calculated [mm M and I when measured R'i is 0.10 second or less.11 is calculated from RT and i when measured A1 is 4 Hz. or less.

1 1 Example 30 Sound-dampening laminates wereprepared as in Example 29and tested at difierent temperatures. Base and constraining layers were0.024 inch thick cold rolled sheet steel. The visco-elastic layer, ofthe same composition as in'Example 29, was 0.017 inch thick. The resultsare recorded in Table 8. These results show that sounddampening betweenabout 50 and 300 \F. was excellent, the best performance being obtainedbetween 160 and 200 F.

TABLE 8 Sound-dampening properties of laminates bonded with Nexus P-1003at various temperatures Low-temperature tests At 1 t I d 1 db 4 RT 5High-temperature tests I At: Width (in Hz.) oi the frequency-resonancepeak at the hall power points (that is, 3 db below the peak).

1 i= Frequency (in Hz.) at the resonance peak.

l db=Ampiitude (in db) of the frequency-resonance peak.

I RT Reverberation time (the time, in seconds, required for a. decreaseof 60 db in the sound level).

RT is calculated from M and I when measured ET is 0.10 Al is 4 Hz.

or ess.

Example 31 To show the benefits of our composition as an adhesive andwater resistant layer on bridge decks, a concrete bridge deck wasprepared for surfacing by removing deteriorated concrete, heavy depositsof grease and oil, loose dirt and debris and sharp protrusions byconventional methods. A rubberized adhesive and primer composition of15% acrylonitrile-butadiene copolymer in high boiling tar oil is heatedin a tar kettle to a temperature of about 300-310 F. Immeditaelythereafter the primer is applied to the bridge deck to a thickness ofabout 25-40 mils by pouring the material onto the bridge deck andspreading the material using a squeegee. The adhesive and waterresistant membrane ofour invention having the following composition:

Coal-tar pitch 150 c. /3 Ethylene-vinyl acetate copolymer (Elvax 260)Ethylene acrylic acid copolymer (EAA 9060) l6 and a thickness of 40 milsis laid over the rubberized adhesive. Care is taken to overlap thesheets. The laps are sealed with small amounts of the rubberizedadhesive. A bituminous binder mix is applied immediately thereafter. Themix should be at a minimum temperature of 290 F., preferably above 300F. during installation. The compacted thickness of the bituminous layeris preferably about The binder mix is then covered with a wearing coursemix with specifications that meet local codes or requirements. Bridgespaved using this procedure give a greater bond between the-bituminouscourse and the concrete. When degradation of the bituminous course doesoccur, the adhesive and water resistant membrane affordsprotection'tothe concrete until corrective meas ures are taken.

Example 32 To show the benefits obtained from our composition in coatingmetal culverts, a galvanized copper bearing steel coil 16 gage x 27%"widehaving a 2 oz. per sq. ft. galvanized coating and meeting AASHOspecification M- Coal-tar pitch 150 0. /5 Ethylene-vinyl acetatecopolymer (Elvax 260'), Ethylene acrylic acid copolymer (EAA 9060) /3The galvanized steel substrate is cleaned by conventiorial methods andis primed with an extremely thin (0.00025" dry thickness) coating havingthe following composition:

.Percent Ethylene-acrylic acid copolymer (EAA 9300) I. 20 NH OH (28% NH4.2 Water 75.8

The primed steel is then heated to a temperature of 400 F., and theadhesive composition is applied as a 20 mil film to the primed topsurface of the hot steel by feeding it between two rubber nip-rolls. Thecoated steel, after laminating, is cooled by water quenching at roomtemperature.

The coil is made into a culvert by the spiral lock-seam method byputting on a pay-off reel and passed through 11 roll forming strands toform a corrugated configuration in the coil sheet product. Thecorrugated sheet is then passed over a mandrel to form thespirallock-seam culvert (24 inch diameter) which is continuously cuttothe desired length of 20 feet. 1

Similarly the coated steel (galvanized or carbon steel) may be formed byconventional means and fabricated into silos, tanks, either for above orbelow ground use, tunnel liners, irrigation pipe, etc., where thecomposition acts as a corrosion preventive coating.

Example 33 A length of 2 inch diameter steel shot-blasted steel pipe isplaced on a conventional coal-tar enamel (CTE) coating line. Sevenventuri gas burners are installed ahead of the CTE coating section. Thecoating tape dispenser is filled with a paper-polyethylene-copolymerresin .tape. This tape is 4" wide with a 3 /2" wide polyethylene coatedkraft paper backing exposed copolymerresin on one edge). The copolymerresin portion of the tape is 0.0095" thick and has the followingcomposition:

Coal-tar pitch (150 C.) /3 Ethylene-vinyl acetate copolymer (Elvax 260)Ethylene acrylic acid copolymer (EAA 9060) /3 The CTE line is started.The pipe advances witha spiralling motion at about 10 ft./min., isheated to about- 220 F. under the gas burners and is wrapped with thetape. After air cooling, the taped pipe was examined and the tape-pipebond rated excellent.

Example 34 This example is to show the beneficial results obtained whenan ethylene-vinyl acetate carboxylic terpolymeris used in place of themixtures of ethylene-vinyl acetate and ethylene-carboxylic acidcopolymers. The procedure of Example 1 was used. The terpolymer testedhad the melt index and composition set forth in Table 9. Table 10 setsforth the adhesive properties of these terpolymers alone and of acomposition comprising terpolymer and 25% coal-tar pitch having aring-and-ball softening point of about C. TABLE 9 Percent 01- Melt Vin 1A51 lie Terpolymer No. index Ethylene acetai e a eid TABLE Properties ofterpolymer No.-

75% tarp 75% terp., 75% terp 1 a %coal- 100% 25%co 100% %cc Blend terp.or pitch terp. tar pitch terp. tar pitch Application conditions:

Temperature, F 350 300 400 300 400 350 Pressure, p.s.i-.. 50 50 50 50 5050 e, minutes 30 30 30 30 30 30 Tensile shear strength 40 15 30 75 60 7050 65 145 35 35 15 Tensile strength, p.s.i 1,950 2,050 2,050 2,850 8001,600 Elongation, percent 600 500 675 025 750 600 Tear resistance,p.p.i.- 225 325 275 850 150 250 Hardness:

Example 35 To show the benefits of the composition when used as acurtain wall panel, test specimens were prepared by cleaning a baselayer of 22 gage galvanized steel having a zinc coating weight of 1%oz./sq. ft. and applying to it a mil layer of a coating of our inventionhaving the following composition:

Coal-tar pitch (150 C.) Va Ethylene-vinyl acetate copolymer (Elvax 260)/a Ethylene acrylic acid copolymer (EAA 9060) 1 3 This coating wasapplied to the base layer by heating to a temperature of about 420-430F. and passing it through a nip-roll to uniformly bond the base layer tothe adhesive layer. The laminate was then reheated to a temperature of400 F. by means of radiant heater and was passed under a series of binscontaining crushed steel mill slag. The first of these bins containedslag particles in the size range between plus 4 mesh and /2 inch; thesecond containing slag sized in the range of plus 10 and minus 4 meshand the third, containing slag of minus 10 mesh size. The aggregatecontaining bins were vibrated as the laminate passed under them allowingthe particles to'fall through screens and onto the laminate. Theaggregate containing composition was then passed through a soft rubberroller to embed the aggregate and the adhesive layer. After quenching bymeans of a water spray the composition was flipped over to allow anynon-adhering aggregate to fall out.

The finished composition was then tested at temperatures ranging from 40F. to 150 F. The adhesion of the three layers was not adverselyafiected.

We claim:

1. A composition comprising:

(a) from about 10 to about 75 weight percent coal-tar pitch;

(b) from about 25 to about 90 weight percent of a polymeric ethylenecomposition selected from (1) a terpolymer of about 60-75 percent byweight ethylene, 15-40 percent vinyl acetate, and 220 percentethylenically-unsaturated carboxylic acid containing from 3 to 8 carbonatoms, and

(2) a mixture of copolymers of ethylene and about 5-50 weight percentvinyl acetate and ethylene and 0.1-75 weight percentethylenically-unsaturated carboxylic acid containing from 3 to 8 carbonatoms wherein the ethylene-vinyl acetate copolymer and theethylene-carboxylic acid copolymer each comprise from about 5 to about85 weight percent of the total composition.

2. The composition of claim 1 wherein the coal-tar pitch is from about25 to about 50 weight percent of the composition, the ethylene-vinylacetate copolymer is from about 20 to about 40 weight percent of thecomposition and the ethylene-carboxylic acid copolymer is from about 20to about 40 weight percent of the composition.

3. The composition of claim 1 comprising substantially equal parts byweight of said pitch, said ethylene-vinyl acetate copolymer and saidethylene-carboxylic acid 00- polymer.

4. The composition of claim 1 wherein finely divided filler material isadded.

5. The composition of claim 1 wherein the ethylenecarboxylic acidcopolymer has an acid content of from about 0.1 percent to about 75percent by weight.

6. The composition of claim 1 wherein the ethylenecarboxylic acidcopolymer has an acid-content of from about 0.1% to about 40% by weight.

7. The composition of claim 1 wherein the ethylenecarboxylic acidcopolymer has an acid content of fro about 2 to about 20% by weight.

8. The composition of claim 1 wherein the carboxylic acid is acrylicacid.

9. The composition of claim 8 wherein the ethyleneacrylic acid copolymerhas a melt index between about 0.1 and 400 and the ethylene-vinylacetate copolymer has a vinyl acetate content of from about 15 to about'40 weight percent and a melt index between 0.5 and 175.1

10. The composition of claim 1 wherein the ethylenevinyl acetatecopolymer has a vinyl acetate content of from about 5 to about 50 weightpercent.

11. The composition of claim 1 wherein the ethylenevinyl acetatecopolymer has a melt index of from about 0.2 to about 500. j

12. The composition of claim 1 comprising from about 25 to about 50weight percent pitch having a softening point between about and C., fromabout 20 .110 about 40 weight percent of an ethylene-acrylic acidcopolymer having an acrylic acid content of from about 2 to about 20weight percent and a melt index between about 5 and 40, and from about20 to about 40 weight percent of an ethylene-vinyl acetate copolymerhaving'aa vinyl acetate content of from 15 to about 40 weight percentand a melt index of from 0.5 to about 175. v

13. The composition of claim 12 comprising substantially equal parts byweight of pitch, ethylene-acrylic acid copolymer and ethylene-vinylacetate copolymer.

14. The composition of claim 1 comprising from about 25 to about 50weight percent pitch having a softening point between about 100 and 150C., and from about 50 to about 75 weight percent of an ethylene-vinylacetate-acrylic acid terpolymer having a vinyl-acetate cohtent of fromabout 15 to about 40 weight percent, an acrylic acid content of fromabout 2 to about 25 weight percent, and a melt index between about 5 and60.

3,814,712 15 16 15. The composition of claim *l-wherein-thecarboxylicFOREIGN PATENTS acid is maleic acid and the ethylenervinyl acetatecopolymer has a vinyl acetate content of from about 15 to about 10410659/1966 Great Bntam 260 897 B 40 weight percent and a melt indexv of fromabout 0.5 to MORRIS LIEBMAN Primary Examiner about 175. v v v.

16. A protective tape useful forwlfapping pipe .com'pfis- 5 H FLETCHERAsslstant Exammer ing a 10 to 50 mil thick sheet of the composition ofclaim 1. US. 01. X.R.

References Cited 260-41 A, 41 B, 80.8, 897 B UNITED STATES PATENTS' 10 r3,361,192 1/1968 Parkinson 260-285 AV 3,298,855 1/1967 Helin et a].117-76 P UNITED STATES PATENT OFFICE 7 CERTIFICATE OF CORRECTION PatentNo. 3 a 814 712 Dated I June 4 1974 lnventor(s) George nyder et al.

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

Column 5,;1ine 73, "coatings" shouldread coating Column 6, line 46."agreate" should read aggregate Table 5, under headingEx. '25, the firstthree line state "23-2/3'4' they should read instead 23 1/3 Signed andsealed this 29th day of October 1974.

(SEAL) Attest;

MCCOY M. GIBSON, JR. (3. MARSHALL DANN AttestingOfficer Commissioner ofPatents FORM Po-1os (10-69) USCOMM-DC seam-pee u.s covsnumsm PRINTINGOFFICE 8

